This invention relates to refrigerator doors, wall panels, ceiling and floor units and the like which are constructed with insulative material foamed in their interiors and in particular is concerned with a retainer used in such doors and the like which seals the insulative material in their interiors during the foaming process.
A door for use in equipment such as refrigerators is manufactured by assembling together separate shell and pan portions with a retainer to form a hollow interior in which the insulative material is located. Various types of insulative materials have been used, foamed plastic such as polyurethane having become popular. In many instances the foamed plastic which has adhesive properties is used in place of mechanical fasteners to hold the shell, pan and retainer together in the finished door. A door of this type is known in the trade as being of the foamed-in variety.
The manufacture of a door of the foamed-in variety involves inserting respective edge portions of the shell and pan into opposed slots of the retainer in a fixture. The foamable insulative material then is loaded into the enclosure so formed and heat is applied to expand the foamable material into the otherwise hollow enclosure. During the foaming process, the fixture maintains the positions of the shell, pan and retainer relative to each other and resists the pressure exerted by the foaming material on the shell and pan which would otherwise distort the shape of the finished door. An example of such a door is the door disclosed in U.S. Pat. No. 3,226,367 to Monti which disclosed a gasket and retainer assembly for such a door.
A problem with the door of the foamed-in variety is that the insulative material leaks out of the interior of the door onto the exterior surfaces of the shell and pan during the foaming process, requiring a hand cleaning step of the door after the door has been formed. This leakage occurs at the seams between the retainer and the shell and pan and results from the retainer being made of a hard inflexible material which does not easily conform to the irregular surfaces of the shell and pan. It is, therefore, often impossible to obtain a positive seal between the retainer and shell and pan. This problem of leakage is aggravated when the surfaces of the shell and pan are embossed or textured as is popular today.